This invention relates to a yarn winding method and apparatus.
In the process for the manufacture of yarn of synthetic fibers, while undrawn yarn, semi-drawn yarn or drawn yarn is travelling from yarn supply sources such as package, the yarn passes through a series of steps, for example, the step of treating yarn, such as the false-twisting step, and the step of winding the treated yarn.
At the yarn winding step, in general, there are disposed many winders to wind up an number of yarns. Bobbins are provided to each of these winders, and when predetermined amounts of yarns are wound on these bobbins, namely when the bobbins become full, the bobbins are taken out from the winder and empty bobbins on which subsequent yarns are to be wound are set to the winder. Then, the winding operation is started again to wind yarns on these empty bobbins. In short, the bobbin exchange operation is inevitably conducted at the winding step. This bobbin exchange operation will now be described by reference to the accompanying drawing.
FIG. 1 is a diagram illustrating an instance of the process including the yarn treating step and the yarn winding step. Referring to FIG. 1, the process includes the yarn treating step A where a yarn 2 taken out from a package 1 is passed through a first feed foller 3, a false twister 4, a second feed roller 5 rotated at a speed higher than the rotation speed of the first feed roller 3, an interlacing element 6 disposed according to need and a third feed roller 7 in succession, and the yarn winding step B where the yarn 2 fed from the step A is passed through a winder 12 including at least a traverse fulcrum guide 8, traversing means 9 and a rotary element 11 for rotating a bobbin 10. A guide roller 13, a suction gun 14 or other device is disposed between the two steps A and B. Incidentally, the yarn from the false twister 4 of the treating step A is heated by a hot plate 15 and is then heat-set by a hot plate 16. When a predetermined amount of the yarn is wound on the bobbin 10 in the winder 12 and the bobbin 10 becomes full, the rotary element 11 of the winder 12 is stopped and the full bobbin is taken out from the winder 12, and an empty bobbin is set thereto instead and the yarn winding operation is started again on this empty bobbin. This operation of taking out a full bobbin from the winder and setting an empty bobbin thereto is ordinarily called "the bobbin exchange operation" in the art.
Even during the bobbin exchange operation, supply of the yarn to the winding step B is continued unless travelling of the yarn 2 running through the treating step A is stopped. There is ordinarily adopted a method in which travelling of the yarn 2 passing through the treating step A is continued even during the bobbin exchange operation, the yarn 2 running from the step A to the step B is continuously sucked by the suction gun 14 during the bobbin exchange operation and the yarn sucked during the bobbin exchange operation is disposed of as waste. After completion of the bobbin exchange, namely after setting an empty bobbin 10 to the winder 12 and completing the preparation for winding the yarn on the empty bobbin 10, the yarn sucked on the suction gun 14 is introduced to and wound on the empty bobbin 10 being rotated. Thus, one cycle of the bobbin exchange operation is completed.
According to this conventional method, it is possible to perform the bobbin exchange operation in the respective winders of one winding machine independently without stopping entirely this winding machine including a plurality of winding units, each having one winder as mentioned above (accordingly, the yarn treating step A includes a plurality of yarn treating units). Therefore, this method is advantageous in that a very high operation efficiency can be attained. However, the time required for completion of the bobbin exchange operation in one winding unit is about 20 seconds, and the amount of the yarn to be sucked by the suction gun during this period and disposed of as waste is considerable. With recent increase of the treating capacity at the treating step, also the amount of waste formed during the bobbin exchange operation is increased and it is sometime as large as 1% of the product yarn. From the viewpoint that resources on the earth should be saved, generation of a large quantity of such waste is not preferred.
Under such background, we have conducted research with a view to developing a method in which the amount of waste produced during the bobbin exchange operation in a winding machine including a number of winding units can be remarkably reduced, and found that production of waste can be markedly reduced by adoption of a specific winding method. It also was found that this winding method can be practised very effectively by adoption of a specific winding apparatus created as means for practising this winding method.